An object of the present invention is to accurately control temperatures of microorganisms or the like. In the present invention, a temperature controller comprises a plurality of cells for storing microorganisms or the like, heaters, and a cooling section. The heaters selectively heat the plurality of cells, and the cooling section wholly cools the plurality of cells. When the maximum value of temperature of a plurality of places is not lower than a first lower limit, the cooling section is driven. When a temperature of one place is not higher than a first lower limit, the heater to heat the place is driven. When the maximum value is not higher than a second lower limit, the cooling section is stopped. When a temperature of one place is not lower than a second upper limit, the heater to heat the place is not driven.